In process control for temperature, pressure, or the like, generally PID control, which is a linear control logic, is used. See, for example, Japanese Patent No. 4358674. Insofar as the control characteristics are nearly linear characteristics, this is applied to control of process gain as well.
Examples of control technologies that use PID include technologies that increase the probability of achieving stabilized control for achieving energy conservation in a range that, for example, does not lead to excessive compromising of the living environment in the case of air conditioning control. See, for example, Japanese Unexamined Patent Application Publication 2013-2748 (“the JP 748”). Moreover, there are technologies that attempt to achieve energy conservation while preventing reductions in intellectual productivity. See, for example, Kana MIZUTANI, et al., “Development of a Variable Air Conditioning Controlling Technology Based on Occupant Satisfaction Levels (Report 3): Occupant Satisfaction Levels and Energy Consumption in a Varying Room Temperature Environment”, Air Conditioning/Hygiene Engineering Conference Compendium, September 2012 (“Mizutani”). In such technologies, the set points in PID control are assertively in moved up and down, and the process variables are caused to track thereto, so as to achieve the objective. Consequently, it is necessary to secure suitable responsiveness.
In linear control logic PID control, when the responsiveness of the feedback control system is increased in order to not lose the linearity of the process gain, there is a limit to the improvement in responsiveness. For example, in the technology disclosed in the JP 748, a phenomenon occurred wherein it was difficult to change the room temperature despite changing the room temperature set point. Moreover, when the control parameters are set so as to overemphasize the control responsiveness, there is the possibility that the stability of control will be lost, resulting in unstable control characteristics.
The present invention is to solve the problems set forth above, and an aspect thereof is to provide a controlling device and controlling method able to increase the responsiveness of feedback control when deliberately varying a process variable for the purpose of energy conservation control, occupant comfort control, or both, without changing a control parameter.